//
// (C) Copyright 2009 Irantha Suwandarathna (irantha@gmail.com)
// All rights reserved.
//

/* Copyright (c) 1995-2000, The Hypersonic SQL Group.
 * All rights reserved.
 *
 * Redistribution and use _in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *
 * Redistributions of source code must retain the above copyright notice, this
 * list of conditions and the following disclaimer.
 *
 * Redistributions _in binary form must reproduce the above copyright notice,
 * this list of conditions and the following disclaimer _in the documentation
 * and/or other materials provided with the distribution.
 *
 * Neither the name of the Hypersonic SQL Group nor the names of its
 * contributors may be used to endorse or promote products derived from this
 * software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED. IN NO EVENT SHALL THE HYPERSONIC SQL GROUP,
 * OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 *
 * This software consists of voluntary contributions made by many individuals
 * on behalf of the Hypersonic SQL Group.
 *
 *
 * For work added by the HSQL Development Group:
 *
 * Copyright (c) 2001-2008, The HSQL Development Group
 * All rights reserved.
 *
 * Redistribution and use _in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *
 * Redistributions of source code must retain the above copyright notice, this
 * list of conditions and the following disclaimer.
 *
 * Redistributions _in binary form must reproduce the above copyright notice,
 * this list of conditions and the following disclaimer _in the documentation
 * and/or other materials provided with the distribution.
 *
 * Neither the name of the HSQL Development Group nor the names of its
 * contributors may be used to endorse or promote products derived from this
 * software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED. IN NO EVENT SHALL HSQL DEVELOPMENT GROUP, HSQLDB.ORG,
 * OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */


using System;
using EffiProzDB.RowIO;


namespace EffiProzDB
{

    // fredt@users 20020221 - patch 513005 by sqlbob@users (RMP)
    // fredt@users 20020920 - path 1.7.1 - refactoring to cut mamory footprint
    // fredt@users 20021205 - path 1.7.2 - enhancements
    // fredt@users 20021215 - doc 1.7.2 - javadoc comments

    /**
     *  The parent for all AVL node implementations, features factory methods for
     *  its subclasses. Subclasses of Node vary _in the way they hold
     *  references to other Nodes _in the AVL tree, or to their Row data.<br>
     *
     *  nNext links the Node objects belonging to different indexes for each
     *  table row. It is used solely by Row to locate the node belonging to a
     *  particular index.
     *
     *
     * @author Thomas Mueller (Hypersonic SQL Group)
     * @version 1.7.2
     * @since Hypersonic SQL
     */
    public abstract class Node
    {

        public const int NO_POS = CachedRow.NO_POS;
        public int iBalance;    // currently, -2 means 'deleted'
        public Node nNext;       // node of next index (nNext==null || nNext.iId=iId+1)

        public static Node newNode(Row r, int id, Table t)
        {

            switch (t.getIndexType())
            {

                case Index.MEMORY_INDEX:
                    return new MemoryNode(r);

                case Index.POINTER_INDEX:
                    return new PointerNode((CachedRow)r, id);

                case Index.DISK_INDEX:
                default:
                    return new DiskNode((CachedRow)r, id);
            }
        }

        public static Node newNode(Row r, RowInputInterface inf, int id,
                                  Table t)   {

        switch (t.getIndexType()) {

            case Index.MEMORY_INDEX :
                return new MemoryNode(r);

            case Index.POINTER_INDEX :
                return new PointerNode((CachedRow) r, id);

            case Index.DISK_INDEX :
            default :
                return new DiskNode((CachedRow)r, inf, id);
        }
    }

        /**
         *  This method unlinks the Node from the other Nodes _in the same Index
         *  and from the Row.
         *
         *  It must keep the links between the Nodes _in different Indexes.
         */
        public abstract void delete();

        /**
         *  File offset of Node. Used with CachedRow objects only
         */
        public abstract int getKey();

        /**
         *  Return the Row Object that is linked to this Node.
         */
        public abstract Row getRow();

        /**
         *  Getters and setters for AVL index operations.
         */
        public abstract bool isLeft(Node node);

        public abstract bool isRight(Node node);

        public abstract Node getLeft();

        public abstract void setLeft(Node n);

        public abstract Node getRight();

        public abstract void setRight(Node n);

        public abstract Node getParent();

        public abstract void setParent(Node n);

        public int getBalance()
        {

            //if (Trace.DOASSERT)
            //{
            //    Trace.doAssert(iBalance != -2);
            //}

            return iBalance;
        }

        public abstract void setBalance(int b);

        public abstract bool isRoot();

        public abstract bool isFromLeft();

        /**
         *  Returns the database table data for this Node
         *
         */
        public abstract Object[] getData();

        public abstract bool Equals(Node n);

        /**
         *  Returns the Node Object that currently represents this Node _in the
         *  AVL index structure. In current implementations of Node this is
         *  always the same as the this Object for MEMORY and TEXT tables but can
         *  be a different Object for CACHED tables, where DiskNode Objects may
         *  be freed from the Cache. Calling this method returns a Node with
         *  currently valid pointers to its linked AVL Nodes.
         *
         */
        public virtual Node getUpdatedNode()
        {
            return this;
        }

        /**
         *  Writes _out the node _in an implementation dependent way.
         */
        public abstract void write(RowOutputInterface _out);

        public bool isDeleted()
        {
            return iBalance == -2;
        }
    }
}
